JP2010079960A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To rapidly perform recording or playback to/from a desired layer without performing adjustment processing for correcting aberration such as spherical aberration for each layer in an optical disk device for performing recording or playback of an optical disk having a plurality of recording or playback layers. <P>SOLUTION: In the optical disk device including an adjustment controller correcting spherical aberration of an optical pickup in a prescribed position and a total reflection light quantity signal detecting means holding a detection interval in each layer obtained by driving an objective lens in a focus direction, on the basis of the optimum position or the corrected amount of spherical aberration adjusted and calculated in one layer and the detection interval of each layer detected by the total reflection light amount signal detecting means, the optimum position or the corrected amount of spherical aberration of each of other layers is calculated and set without performing adjustment at the other layers. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus that performs recording or reproduction on an optical disc having a plurality of recording or reproducing layers.

  As a method for correcting spherical aberration of an optical disk, Patent Document 1 states that “spherical aberration and depth of focus are coarsely adjusted simultaneously using tracking error signal amplitude (PP amplitude) and reproduced signal amplitude (RF amplitude) is used. Make fine adjustments. ”

JP 2005-1000048 A

  With the recent increase in capacity of video information, computer data, etc., as an optical disk medium for storing them, development of Blu-ray Disc, which is a medium with higher recording density than CD and DVD, and information on those disks An optical disc apparatus that records or reproduces data has been developed. At present, Blu-ray Disc has a commercially available disc with 50 GB of two recording or reproducing layers, and the distance between the recording or reproducing layers is 25 μm, which is very narrow compared with 55 μm of the conventional DVD. Yes.

  In general, the spherical aberration in the optical mechanism is proportional to the error of the distance (cover layer) from the disc surface on the objective lens side to the recording or reproducing layer and the fourth power of the numerical aperture (NA) of the objective lens. Due to the occurrence of spherical aberration, the light spot on the disk surface is defocused. Therefore, compared to conventional CDs and DVDs, the Blu-ray Disc with a smaller cover layer and a larger NA is used for each recording or reproducing layer that is not used with a CD or DVD. Therefore, a means for appropriately correcting spherical aberration is required.

  In the future, for the purpose of further increasing the capacity, the development of higher-density multilayer discs having three or more recording or reproducing layers and the development of devices capable of recording or reproducing information on multilayer discs will be carried out. Is expected. Here, in an optical disc apparatus compatible with high-density multilayer discs, when adjustment processing for correcting aberrations such as spherical aberration is performed for each layer, it takes time to perform recording or reproduction on a desired layer. Also, there is a problem that the software configuration for realizing the adjustment process for correcting the aberration mounted on the apparatus becomes complicated.

  An object of the present invention is to provide an optical disc apparatus capable of shortening the time for acquiring the correction amount of aberration for each layer.

  The above problem is solved by, for example, the invention described in the claims.

  According to the present invention, it is possible to provide an optical disc apparatus capable of shortening the time for acquiring the aberration correction amount for each layer.

  Hereinafter, some examples which are embodiments in which the present invention is adopted in an optical disc apparatus will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration example of an optical disc apparatus.

  An optical disc apparatus 100 in FIG. 1 performs recording or reproduction on an optical disc 1 having a plurality of recording or reproduction layers.

  An optical pickup 2 that is an optical mechanism includes a laser emission control circuit 3, a laser light source 4 that emits a laser based on a signal from the laser emission control circuit 3, and a laser beam from the laser light source 4 for the optical disc 1. It includes an objective lens 5 that emits light and a detector 6 that receives reflected light from the optical disk 1.

  The optical pickup 2 includes a focus actuator 7 that drives the objective lens 5 in the focus direction, and a focus error signal detection circuit 8 that detects a focus error signal based on a signal from the detector 6 and holds a detection time. A focus drive circuit 9 and a focus actuator driver 10 that control the focus actuator 7 based on a signal from the focus error signal detection circuit 8 are provided.

  Further, based on the light reception signal in the detector 6 generated by driving the objective lens 5 in the focus direction at the moving speed set in the focus drive circuit 9, the sum signal of the reflected light amount in each layer is detected and the detection interval is set. A total reflection light amount signal detection circuit 11 is provided.

  In addition, an aberration correction mechanism 12 that corrects aberrations in the optical pickup 2, an aberration correction mechanism drive circuit 13 for driving the aberration correction mechanism 12, and an aberration correction mechanism driver 14 are provided. The aberration correction mechanism 12 generates, for example, different refractive index distributions at the inner periphery and the outer periphery of the light beam, so that the optical distance of the light beam that passes through the inner periphery side of the objective lens 2 and the optical distance of the light beam that passes through the outer periphery side. This is a mechanism for reducing the difference in distance. In addition, the aberration correction mechanism 12 can be configured using, for example, a movable convex lens and a concave lens. The aberration correction mechanism 12 corrects the aberration by adjusting the positions of the movable convex lens and the concave lens, for example. Then, an amount for correcting the difference between the optical distance of the light beam passing through the inner peripheral side and the optical distance of the light beam passing through the outer peripheral side is defined as a correction amount.

  Further, a recording signal detection circuit 15 for detecting jitter, the number of errors, an RF signal and the like based on a signal from the detector 6 of the recording unit in each layer is provided.

  Further, based on the information obtained from the aberration correction mechanism drive circuit 13 and the recording signal detection circuit 15, the optimum position of the aberration correction mechanism 12 is calculated so as to meet the recording or reproduction conditions. The adjustment controller 16 for setting the calculation result is provided.

  In the optical disc apparatus 100 of this embodiment, the adjustment controller 16 adjusts and calculates the optimum position or correction amount of the aberration correction mechanism 12 in a certain layer, the moving speed in the focus drive circuit 9, and the total reflected light signal detection circuit. The optimal position or correction amount is calculated and set based on the detection interval of the reflected light amount signal detected in step 11 without adjustment in other layers.

  Next, the detection interval of the reflected light amount signal in each layer detected by the total reflected light amount signal detection circuit 11 and the layer and layer thickness calculated from the detected interval will be described with reference to FIG.

  In FIG. 2, when the objective lens 5 is driven in the focus direction, the focus drive circuit 9 generates a focus drive signal based on the moving speed of the objective lens 5. Thus, the reflected light amount signal is obtained from each recording or reproducing layer of the optical disc 1 by driving the objective lens 5 in the focusing direction, and the state where each layer is in focus is set as a peak (peak) as shown in FIG. The signal to be detected is detected by the total reflection light amount signal detection circuit 11. Based on the detected reflected light amount signal, the total reflected light amount signal detection circuit 11 generates a peak detection signal for each layer, calculates the time interval between the layers based on the peak detection signal, and holds the detection interval. . For example, the interval from the surface of the optical disc 1 to the first layer is T0, the interval from the first layer to the second layer is T1, and the interval from the first layer to the third layer is T2.

  Here, one of the causes of the spherical aberration generated in the optical pickup 2 is a difference in the layer thickness of the optical disc 1. Therefore, the optimum position or correction amount of the aberration correction mechanism calculated by the adjustment controller 16 for each layer has a correlation with the thickness of the layers of the optical disc 1. Information (distance) between layers can be obtained from the moving speed (distance / time) in the focus drive circuit 9 and the time calculated based on the peak detection signal in the total reflected light amount signal detection circuit 11. Therefore, the adjustment controller 16 uses the optimum position or correction amount of the aberration correction mechanism 12 adjusted and calculated in a certain layer, and is detected by the moving speed in the focus drive circuit 9 and the total reflected light amount signal detection circuit 11. Based on the detection interval of the reflected light amount signal in each layer, the optimum position or correction amount for the other layer can be calculated and set from the information of the layer and the layer thickness without adjusting in the other layer.

  The correction amount is, for example, a table in which the detection interval is associated with the change amount of the aberration correction amount in the adjustment controller 16, and the correction amount corresponding to the measured detection interval or the change amount thereof. Can be obtained by calculating. The values held in the table may be held in the adjustment controller 16 in advance, for example, by a test when the optical disc apparatus 100 is manufactured. Further, the adjustment controller 16 may be configured to hold a table of the aberration correction amount and the change amount for each type of optical disk and each manufacturer.

  Since the refractive index of the medium constituting the optical disc 1 is larger than that of air, the aberration becomes larger as the layer to be focused becomes the deeper layer when viewed from the optical pickup 2 side. Therefore, the optical disc apparatus 100 according to the present embodiment calculates and obtains a larger correction amount than the correction amount for the front layer when focusing on the layer on the back side as viewed from the optical pickup 2 side. Become.

  Next, the operation of the optical disc apparatus 100 in the present embodiment will be described using the flowchart of FIG.

  First, when the optical disk 1 is mounted on the optical disk apparatus 100, the objective lens 5 is driven in the focus direction at a predetermined moving speed via the focus actuator driver 10 in response to a command from the focus drive circuit 9 (S101), and total reflection occurs. In the light amount signal detection circuit 11, a reflected light amount signal for each layer is acquired and a peak detection signal is generated (S102). Further, the focus driving circuit 9 controls the objective lens 5 so as to be in a desired recording or reproducing layer (S103). Thereafter, the adjustment controller 16 performs aberration adjustment at a predetermined position, and calculates the optimum position or correction amount of the aberration correction mechanism 12 so as to meet the recording or reproduction conditions in a desired layer (S104). Further, the adjustment controller 16 uses the optimum position or correction amount of the aberration correction mechanism 12 calculated in one layer, and does not adjust in the other layers, so that the moving speed and total reflected light amount signal detection circuit in the focus drive circuit 9 are adjusted. Based on the detection interval of the reflected light amount signal in each layer detected in 11, the optimum position or correction amount for the other layers is calculated and set (S105).

  As described above, in the first embodiment, the adjustment controller 16 uses the optimum position or correction amount of the aberration correction mechanism 12 adjusted and calculated in a certain layer, the moving speed in the focus drive circuit 9, and the total reflected light signal detection circuit 11. From the information of the layer and layer thickness based on the detection interval of the detected reflected light amount signal, it is possible to calculate and set the optimal position or correction amount for other layers without adjusting with other layers, The aberration of each layer can be quickly corrected for the optical disc 1 having a plurality of recording or reproducing layers.

  Since the configuration of the optical disc apparatus 100 according to the second embodiment is the same as that of FIG. 1 according to the first embodiment, the description of the apparatus configuration is omitted.

  Further, the detection interval of the reflected light amount signal of each layer detected by the total reflected light amount signal detection circuit 11 in the second embodiment, and the layer and layer thickness information calculated from the detected interval are described in the first embodiment. Since it is the same as that of FIG.

  FIG. 4 is an example of the optical disc 1 having a plurality of recording or reproducing layers, and is a cross-sectional view of the optical disc 1.

  In the optical disc 1 of FIG. 4, the disc information related to the optical disc 1 such as a disc type such as Blu-ray Disc, the number of disc layers, and the disc manufacturer is recorded on the third layer from the disc surface (101). ).

  In the optical disc apparatus 100 of this embodiment, the adjustment controller 16 adjusts and calculates the optimal position or correction amount of the aberration correction mechanism 12 in the layer in which the disc information of the optical disc 1 is recorded among the plurality of recording or reproduction layers. Based on the moving speed in the focus drive circuit 9 and the detection interval of the reflected light amount signal detected by the total reflected light signal detection circuit 11, the optimum position or correction amount is calculated and set without adjustment in other layers. It is characterized by that.

  FIG. 5 illustrates the operation of the optical disc apparatus 100 according to the present embodiment with reference to a flowchart.

  First, when the optical disc 1 is mounted on the optical disc apparatus 100, the objective lens 5 is driven in the focus direction at a predetermined moving speed via the focus actuator driver 10 in response to a command from the focus drive circuit 9 (S201). In the light amount signal detection circuit 11, a reflected light amount signal for each layer is acquired and a peak detection signal is generated (S202). Further, the focus driving circuit 9 controls the objective lens 5 so as to be in focus on the recording or reproducing layer where the disc information is recorded at a predetermined moving speed (S203). Thereafter, the adjustment controller 16 adjusts the aberration at a predetermined position, and calculates the optimum position or correction amount of the aberration correction mechanism 12 so as to meet the recording or reproducing conditions in the recording or reproducing layer where the disc information is recorded. (S204). Further, the adjustment controller 16 uses the optimum position or correction amount of the aberration correction mechanism 12 calculated in the layer in which the disc information of the optical disc 1 is recorded among the plurality of recording or reproduction layers, and makes adjustments in other layers. Instead, the optimum position or correction amount for the other layers is calculated and set based on the moving speed in the focus drive circuit 9 and the detection interval of the reflected light amount signal in each layer detected in the total reflected light amount signal detection circuit 11 (S205). ).

  In the second embodiment, the optimum position or correction amount of the aberration correction mechanism 12 calculated by the adjustment controller 16 in the layer in which the disc information of the optical disc 1 is recorded among the plurality of recording or reproducing layers, and the focus driving circuit 9. From the information on the layer and the thickness of the layer based on the moving speed and the detection interval of the reflected light amount signal detected by the total reflected light signal detection circuit 11, the optimum position or The correction amount can be calculated and set, and the aberration of each layer can be quickly corrected for the optical disc 1 having a plurality of recording or reproducing layers.

  Since the configuration of the optical disc device 100 according to the third embodiment is the same as that of FIG. 1 of the first embodiment, the description of the device configuration is omitted.

  In addition, the detection interval of the reflected light amount signal of each layer detected by the total reflected light amount signal detection circuit 11 according to the third embodiment, and the layer and layer thickness calculated from the detected intervals are the same as those in the first embodiment. Since it is the same as that of description of 2, it abbreviate | omits.

  In the optical disc apparatus 100 of this embodiment, the adjustment controller 16 adjusts and calculates the optimum position or correction amount of the aberration correction mechanism 12 in the layer farthest from the optical pickup 2 among the plurality of recording or reproducing layers, and focus driving. Based on the moving speed in the circuit 9 and the detection interval of the reflected light amount signal detected by the total reflected light signal detection circuit 11, the optimum position or the correction amount is calculated and set without adjustment in other layers. And

  Next, the operation of the optical disc apparatus 100 in the present embodiment will be described using the flowchart of FIG.

  First, when the optical disc 1 is mounted on the optical disc apparatus 100, the objective lens 5 is driven in the focus direction at a predetermined moving speed via the focus actuator driver 10 in response to a command from the focus drive circuit 9 (S301). In the light amount signal detection circuit 11, a reflected light amount signal for each layer is acquired and a peak detection signal is generated (S302). Further, the focus drive circuit 9 controls the objective lens 5 so as to be in focus on the recording or reproducing layer farthest from the optical pickup 2 (S303). Thereafter, the adjustment controller 16 performs aberration adjustment at a predetermined position, and calculates the optimum position or correction amount of the aberration correction mechanism 12 with respect to the recording or reproducing layer on which the disc information is recorded (S304). Further, the adjustment controller 16 uses the optimum position or correction amount of the aberration correction mechanism 12 calculated in the layer farthest from the optical pickup 2 among the plurality of recording or reproduction layers, and without adjusting in the other layers, Based on the moving speed in the focus drive circuit 9 and the detection interval of the reflected light amount signal in each layer detected by the total reflected light amount signal detection circuit 11, the optimum position or correction amount for the other layers is calculated and set (S305).

  In the third embodiment, the adjustment controller 16 calculates the optimum position or correction amount of the aberration correction mechanism 12 calculated in the layer farthest from the optical pickup 2 among the plurality of recording or reproduction layers, and the moving speed in the focus drive circuit 9. From the information on the layer and the thickness of the layer based on the detection interval of the reflected light amount signal detected by the total reflected light signal detection circuit 11, the optimum position or correction amount for the other layer can be determined without adjusting the other layer. It is possible to calculate and set, and it is possible to quickly correct the aberration of each layer with respect to the optical disc 1 having a plurality of recording or reproducing layers.

  As described above, according to the optical disc apparatus 100 of each embodiment, the optical disc apparatus having the plurality of recording or reproducing layers is provided with means for optimally correcting the aberration of the optical mechanism so that the desired layer meets the recording or reproducing conditions. It is possible to calculate the correction amount of another layer without adjusting the other layer using the correction amount adjusted and calculated in a certain layer. Furthermore, it is possible to provide an optical disc apparatus 100 that quickly performs recording or reproduction on a desired layer even when adjustment processing for correcting aberration such as spherical aberration is not performed for each layer of an optical disc having a plurality of recording or reproduction layers. Can do.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  In addition, each of the above-described configurations may be configured such that some or all of them are configured by hardware, or are implemented by executing a program by a processor. Further, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

1 is a block diagram of an optical disc apparatus according to a first embodiment. Detection interval of the reflected light amount in the first embodiment Flowchart in the first embodiment Sectional drawing of the optical disk in Example 2 Flowchart in the second embodiment Flowchart in the third embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Optical pick-up, 3 ... Laser light emission control circuit, 4 ... Laser light source, 5 ... Objective lens, 6 ... Detector, 7 ... Focus actuator, 8・ ・ ・ Focus error detection circuit, 9 ... Focus control circuit, 10 ... Focus actuator driver, 11 ... Total reflection light amount signal detection circuit, 12 ... Aberration correction mechanism, 13 ... Aberration correction mechanism Drive circuit, 14... Driver for aberration correction mechanism, 15... Recording signal detection circuit, 16.

Claims (5)

In an optical disc apparatus that performs recording or reproduction on an optical disc having a plurality of recording or reproduction layers,
An objective lens for condensing laser light on each layer of the optical disc;
A photodetector that generates a light reception signal based on reflected light from the optical disk of the laser beam condensed by the objective lens;
A focus actuator for changing a focus position of the objective lens;
A focus control means for controlling the focus actuator so that the laser beam is focused on a desired layer based on an error in a focus direction between a focused position and an actual position in each layer;
A reflected light amount detecting means for detecting a sum signal of reflected light amounts in each layer generated by driving the objective lens in a focus direction and holding a detection interval;
Aberration correction means for correcting the aberration of the objective lens;
A recording signal detecting means for detecting a signal recorded in each layer based on a light receiving signal detected by the photodetector;
A correction amount control means for adjusting a correction amount of the aberration correction means so that a signal obtained from the recording signal detection means matches a recording condition or a reproduction condition,
The correction amount control means includes a correction amount of the aberration correction means adjusted based on a received light signal in a certain one of the plurality of recording or reproducing layers and a reflection detected by the reflected light amount signal detection means. An optical disc apparatus, wherein a correction amount in another layer is acquired based on a detection interval of a light amount signal. The optical disc apparatus according to claim 1,
The optical disc apparatus, wherein the correction amount control means does not adjust a correction amount for the other layer based on a signal obtained by the recording signal detection means in the other layer. The optical disk apparatus according to claim 1,
The correction amount control unit includes a correction amount of the aberration correction unit adjusted based on a light reception signal and a reflected light amount in a layer in which disc information that is information about the optical disc is recorded among the plurality of recording or reproduction layers. An optical disc apparatus characterized in that a correction amount in another layer is acquired based on a detection interval of a reflected light amount signal detected by a signal detection means. The optical disk apparatus according to claim 3,
The optical disc apparatus according to claim 1, wherein the disc information is information indicating any of a disc type, a disc layer number, and a disc manufacturer. The optical disk apparatus according to claim 1,
The correction amount control means is detected by the correction amount of the aberration correction means adjusted based on the received light signal in the layer farthest from the objective lens among the plurality of recording or reproduction layers and the reflected light amount signal detection means. An optical disc apparatus characterized in that a correction amount in another layer is acquired based on the detection interval of the reflected light amount signal.

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